1. Field of the Invention
With reference to the classification of art as established in and by the United States Patent Office, the present invention is believed to be found in the general class entitled "Plastic Article or Earthenware Shaping or Testing Apparatus," and more particularly in the subclasses pertaining to "with apparatus assembly or dismounting means or with idle part." Also of note is the subclass pertaining to "including securing means for retaining separable elements." The mold set of this invention is directed to injection-molding die sets and for portions which are readily removable and are retained with clamp means.
2. Description of the Prior Art
Injection molding and die sets used therewith are well known. The present injection processes propose and practically mandate that attendant time be reduced as much as possible. Short-run changes for molded articles are quite well known and necessary. The "down" or idle time for changeover in and for a machine costing several thousands of dollars and including the attendant's time are costly. For this reason, assured changeover with precise alignment is desired. This injection-molding process and apparatus has been the subject of many U.S. patents, among which are: U.S. Pat. No. 3,111,895 to KRAFT et al, as issued Nov. 26, 1963; U.S. Pat. No. 4,005,964 to BISHOP, as issued Feb. 1, 1977; U.S. Pat. No. 4,348,165 to VOSTROVSKY, as issued Sept. 7, 1982; U.S. Pat. No. 4,472,128 to RUHL, as issued Sept. 18, 1984, and U.S. Pat. No. 4,555,228 to NISHIIKE et al, as issued Nov. 26, 1985.
The patent to Kraft shows die clamp means, but does not pertain to injection molding with easy and rapid exchange of molding die portions. The patent to BISHOP pertains to ejecting and clamping apparatus, but does not utilize the rapid exchange method and apparatus of and as in the present invention. The patent to VOSTROVSKY shows a clamp means for die sections, but this clamp apparatus requires and shows hydraulic cylinders to actuate clamps for the dies. The patent to RUHL (U.S. Pat. No. 4,472,128), although for a locator clamp, has these clamps with springs and uses specially designed and machined holders. These clamps are designed to secure the upper and lower dies and the mold sets are not similarly formed. The U.S. Pat. No. 4,500,275, also to RUHL, uses wedge-shaped and screw-moved clamp means to provide precise location. These clamps are not and do not provide for the removing of portions of a die set initially secured. The patent to NISHIIKE et al is directed to the automotive exchange of complete mold sets.
The above and known patents and die sets do not disclose or teach a mold die set having upper and lower members that are disposed for securing to the molding machine apparatus and, when so placed and secured, the intermediate portions--including the plates into which the cavity is formed--are readily removable and new member portions may be inserted and mounted, then clamped.